JP5308465B2 - Shield printed wiring board - Google Patents

Abstract

The invention relates to a shielded type printed circuit board, which comprises a printed circuit board, a shielding film and a strengthening component. The printed circuit board comprises a base component and an insulation film, wherein a circuit pattern used for ground connection is formed on the base component, the insulation film is arranged on the base component, the circuit pattern used for ground connection is covered by the insulation film, and an electronic component is connected at the installation place of the lower surface of the base component. The shielding film arranged on the printed circuit board comprises an electric conduction layer and an insulation layer, wherein the electric conduction layer is equipotential with the circuit pattern used for ground connection, and the electric conduction layer is arranged on the printed circuit board and is used for covering a part of a zone or the whole zone opposite to the installation place; and the insulation layer is arranged at the electric conduction layer. The strengthening component has electroconductivity and is arranged on the shielding film at the zone opposite to the installation place. The strengthening component is jointed with the insulation layer by electric conductivity cement containing spherical electric conductivity particles. The thickness of the insulation layer is less than the raising length of the electric conductivity particles from the electric conductivity cement under the joint state of the electric conductivity cement and the insulation layer, and the electric conductivity particles are in contact with the electric conduction layer under the joint state of the electric conductivity cement and the insulation layer.

Description

  The present invention relates to a shield printed wiring board used for a mobile phone, a computer and the like.

  2. Description of the Related Art Conventionally, electronic devices such as mobile phones and computers are easily affected by noise such as electromagnetic waves received from the main board or the outside due to downsizing and high-speed processing. Therefore, the demand for a printed wiring board provided with a shield film that shields noise such as electromagnetic waves is increasing. In addition, such printed wiring boards are used by connecting electronic components used in mobile phones, computers, etc., and the mounting site where the electronic components are mounted is distorted due to bending during use. There is. Therefore, a reinforcing member is provided at a position facing the mounting part where the electronic component is mounted.

  For example, FIG. 5 is a view showing a conventional shield printed wiring board 100. As shown in FIG. 5, the shield printed wiring board 100 includes a base member 112 on which ground wiring patterns 114 and 115 are formed, and a base via an adhesive layer 113 so as to cover the ground wiring patterns 114 and 115. The printed wiring board 110 provided with the insulating film 111 provided on the member 112 is provided. On the insulating film 111 of the shield printed wiring board 100, a shield film 120 including a conductive material 123, a conductive layer 122, and an insulating layer 121 in this order is provided. Here, a hole 140 for exposing the ground wiring pattern 114 is formed in the insulating film 111 and the adhesive layer 113 of the printed wiring board 110. By filling the hole 140 with the conductive material 123 of the shield film 120, the conductive layer 122 and the ground wiring pattern 114 are electrically connected, and both are kept at the same potential. Thereby, the electromagnetic wave 90a with respect to the printed wiring board 110 can be shielded by the shield film 120. Furthermore, an electronic component 150 is connected to a mounting portion provided on the lower surface of the printed wiring board 110. A reinforcing member 135 is provided on the printed wiring board 110 at a position facing the mounting part of the electronic component 150.

  Here, the printed wiring board 110 and the electronic component 150 connected to the printed wiring board 110 may be affected by noise such as the electromagnetic wave 90b from the outside, and it is necessary to provide a shielding effect also to a portion where the electronic component 150 is mounted. is there. Therefore, the reinforcing member 135 is made of a conductive material so that the reinforcing member 135 has a shielding effect, and the reinforcing member 135 receives two functions of the reinforcing effect and the shielding effect.

  Here, in order to provide the reinforcing member 135 with a sufficient shielding effect, it is necessary to keep the reinforcing member 135 at the same potential as the ground wiring patterns 114 and 115. Therefore, conventionally, a ground member (not shown) is separately provided outside the shield printed wiring board 100, and the reinforcing member 135 and the ground wiring patterns 114 and 115 are kept at the same potential via the ground member. However, when a grounding member is provided outside the shield printed wiring board 100, wiring for connecting the reinforcing member 135 and the grounding member is necessary, and the area of the shield printed wiring board increases accordingly. There were problems such as narrowing of design freedom.

  Therefore, in the conventional shield printed wiring board 100, the ground wiring pattern 115 is disposed immediately below the reinforcing member 135, and the hole 160 is formed in the insulating film 111 and the adhesive layer 113 so that the ground wiring pattern 115 is exposed. The reinforcing member 135 and the ground wiring pattern 115 were kept at the same potential by forming and filling the hole 160 with the dendritic conductive adhesive 130.

  As a means for keeping the reinforcing member and the ground wiring pattern at the same potential using the above method, for example, there is a flexible printed wiring board disclosed in Patent Document 1. In this flexible printed wiring board, a conductive adhesive is filled in the opening exposing the ground circuit, the metal reinforcing plate and the ground circuit are kept at the same potential, and the metal reinforcing plate has a shielding effect.

JP 2009-218443 A

  However, as described above, when the hole 160 is filled with the conductive adhesive 130, the gaps 160 a and 160 b may be generated in the connection portion between the conductive adhesive 130 and the ground wiring pattern 115. This is because the connecting portion between the conductive adhesive 130 and the ground wiring pattern 115 is sandwiched between upper and lower parts by a hard material such as the reinforcing member 135 and the base member 112, so This is because the conductive adhesive 130 does not sufficiently follow the steps of 160. In such a case, in the reflow process in which the shield printed wiring board 100 is mounted on a main board such as a mobile phone or a computer, the gaps 160a and 160b swell due to heat, and the electrical connection between the conductive adhesive 130 and the ground wiring pattern 115 occurs. Insufficient connection. As a result, there has been a problem that the appearance becomes poor or the reinforcing member 135 cannot be kept at the ground potential, and it becomes difficult to ensure a sufficient shielding effect.

  Further, in order to prevent the gaps 160a and 160b from being generated in the connection portion between the conductive adhesive 130 and the ground wiring pattern 115, it is necessary to increase the thickness of the conductive adhesive 130 as much as possible. In order to maintain conductivity, it is necessary to increase the proportion of the conductive particles present in the conductive adhesive 130, and accordingly, the cost is increased and the efficiency is poor. Furthermore, in the above method, it is necessary to arrange the ground wiring pattern 115 immediately below the reinforcing member 135, and there is a problem that the degree of freedom in design becomes narrow.

  The present invention was made in view of the above problems, and in a printed wiring board to which electronic components are connected, even when a reinforcing member is provided at a position facing the electronic components, while ensuring a degree of freedom in design, It is an object of the present invention to provide a shield printed wiring board capable of maintaining a shielding effect for a mounting part of an electronic component.

  The shield printed wiring board of the present invention includes a base member on which a ground wiring pattern is formed, and an insulating film provided on the base member so as to cover the ground wiring pattern, and the electronic component is included in the base. A printed wiring board connected to a mounting portion provided on the lower surface of the member, a conductive layer having the same potential as the ground wiring pattern and disposed to a region facing the mounting portion, and provided on the conductive layer A shielding film provided on the printed wiring board, and a conductive reinforcing member disposed in a region facing the mounting portion and provided on the shielding film. A shield printed wiring board having the reinforcing member adhered to the insulating layer by a conductive adhesive containing spherical conductive particles; The insulating layer is formed with a layer thickness thinner than the protruding length of the conductive particles protruding from the conductive adhesive after the conductive adhesive is bonded, and the conductive adhesive is formed of the insulating layer. After being adhered to, the conductive particles come into contact with the conductive layer.

  According to the above configuration, the conductive layer having the same potential as that of the ground wiring pattern is disposed on the printed wiring board up to a region facing the mounting part of the electronic component. Thereby, the electromagnetic wave from the outside with respect to the mounting site | part of an electronic component can be shielded with the shield film which has a conductive layer. Moreover, the area | region which opposes the mounting site | part of an electronic component is reinforced with the reinforcement member provided on the shield film. Thereby, the distortion etc. which arise in a mounting site | part resulting from a bending etc. can be prevented with a reinforcement member. Furthermore, since the conductive particles contained in the conductive adhesive that bonds the reinforcing member on the insulating layer of the shield film come into contact with the conductive layer of the shield film after the conductive adhesive is bonded, the conductivity is reduced. The potential of the reinforcing member and the potential of the conductive layer can be set to the same potential, and the reinforcing member can also have a shielding effect. Thereby, a shielding effect can be more reliably brought about by the double effect of the shielding effect by the shielding film and the shielding effect by the reinforcing member on the mounting part of the electronic component. Therefore, in order to make the reinforcing member have the ground potential, it is not necessary to expose the ground wiring pattern and connect the reinforcing member and the ground wiring pattern via the conductive adhesive as in the conventional case. Therefore, it is not necessary to form a wiring pattern for grounding in accordance with the arrangement location, and the degree of freedom in design is improved. Further, since there is no need to connect the reinforcing member and the ground wiring pattern via the conductive adhesive, there is no problem during reflow caused by a gap formed in the connecting portion. As described above, the shielding effect can be maintained while ensuring the degree of freedom of design. Furthermore, since the conductive particles are spherical, the length of the conductive particles protruding from the conductive adhesive is substantially constant in the layer thickness direction regardless of the direction in which the conductive particles are inclined in the conductive adhesive. Thereby, for example, it becomes easier for the conductive particles to break through the insulating layer and to come into contact with the conductive layer as compared with flakes and dendrites. As a result, the reinforcing member and the conductive layer can be more reliably maintained at the same potential.

  In the shield printed wiring board of the present invention, the reinforcing member may be further connected to an external ground member maintained at the same potential as the ground wiring pattern.

  According to the above configuration, the reinforcing member is internally maintained at the same potential as the ground wiring pattern via the conductive particles contained in the conductive adhesive, and is also used for the ground via the external ground member. Since the same potential as the wiring pattern is maintained, the shielding effect can be further improved.

  In the shield printed wiring board of the present invention, the insulating layer of the shield film may be coated on the conductive layer.

  According to said structure, since the insulating layer of a shield film is coated on the conductive layer, it can be made thinner than a film-like insulating layer, for example, and the conductive particle which protruded from the conductive adhesive is the insulating layer. It will be easy to contact with the conductive layer.

  Moreover, the shield printed wiring board of this invention WHEREIN: The said reinforcement member may be formed with the stainless steel material.

  According to said structure, since the stainless steel is the hardness suitable for reinforcement, and it is excellent in corrosion resistance, it can provide the shielding effect with respect to a mounting site | part more effectively, reinforcing the mounting site | part of an electronic component.

  According to the shield printed wiring board of the present invention, it is possible to shield electromagnetic waves from the outside with respect to the mounting part of the electronic component by the shield film having the conductive layer. In addition, the reinforcing member can prevent distortion or the like generated in the mounting portion due to bending or the like. Furthermore, the potential of the reinforcing member having conductivity and the potential of the conductive layer can be made the same potential, and the reinforcing member can also have a shielding effect. Thereby, a shielding effect can be more reliably brought about by the double effect of the shielding effect by the shielding film and the shielding effect by the reinforcing member on the mounting part of the electronic component. Therefore, in order to make the reinforcing member have the ground potential, it is not necessary to expose the ground wiring pattern and connect the reinforcing member and the ground wiring pattern via the conductive adhesive as in the conventional case. Therefore, it is not necessary to form a wiring pattern for grounding in accordance with the arrangement location, and the degree of freedom in design is improved. Further, since there is no need to connect the reinforcing member and the ground wiring pattern via the conductive adhesive, there is no problem during reflow caused by a gap formed in the connecting portion. As described above, the shielding effect can be maintained while ensuring the degree of freedom of design. Furthermore, for example, the conductive particles are more likely to break through the insulating layer and more easily come into contact with the conductive layer than in the form of flakes or dendrites. As a result, the reinforcing member and the conductive layer can be more reliably maintained at the same potential.

It is a partial cross section figure of the shield printed wiring board concerning this embodiment. (A) It is a figure which shows the hole part formation process in the manufacturing method of the shield printed wiring board concerning this embodiment. (B) It is a figure which shows the shield film adhesion process in the manufacturing method of the shield printed wiring board concerning this embodiment. (C) It is a figure which shows the peeling layer peeling process of the shield film in the manufacturing method of the shield printed wiring board concerning this embodiment. (D) It is a figure which shows the conductive adhesive adhesion process in the manufacturing method of the shield printed wiring board concerning this embodiment. (E) It is a figure which shows the reinforcement member adhesion process in the manufacturing method of the shield printed wiring board concerning this embodiment. (F) It is a figure which shows the electronic component connection process which connects an electronic component to the shield printed wiring board concerning this embodiment. It is a figure which shows the experimental result using the Example and comparative example of the shield printed wiring board concerning this embodiment. It is a partial cross section figure of the conventional shield printed wiring board.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Overall configuration of shield printed wiring board 1)
First, the shield printed wiring board 1 of this embodiment is demonstrated using FIG. As shown in FIG. 1, the shield printed wiring board 1 includes a printed wiring board 10, a shield film 20, and a reinforcing member 35. And the electronic component 50 is connected to the mounting site | part provided in the lower surface of the printed wiring board 10. FIG. Further, the shield film 20 is provided on the printed wiring board 10 and is disposed up to a region facing the mounting portion to which the electronic component 50 is connected. Thereby, the shield film 20 is used to shield noise such as the electromagnetic wave 90b from the outside with respect to the mounting part of the electronic component 50.

  Further, the reinforcing member 35 is provided on the shield film 20 and is disposed so as to face the mounting portion to which the electronic component 50 is connected. The reinforcing member 35 is adhered in contact with the conductive adhesive 30, and is adhered to the insulating layer 21 of the shield film 20 by the conductive adhesive 30. Here, the enlarged portion a in FIG. 1 is an enlarged view of the state where the conductive adhesive 30 adhered in a contact state with the reinforcing member 35 is adhered to the insulating layer 21 of the shield film 20. As shown in the enlarged portion a, the conductive particles 32 included in the conductive adhesive 30 protrude from the adhesive 31 included in the conductive adhesive 30. The reinforcing member 35 bonded in contact with the upper surface of the conductive adhesive 30 is in contact with the conductive particles 32. On the other hand, the conductive particles 32 protruding from the lower surface of the conductive adhesive 30 pierce the insulating layer 21 of the shield film 20 and are in contact with the conductive layer 22 therebelow. As a result, the reinforcing member 35 and the conductive layer 22 of the shield film 20 become conductive through the conductive particles 32 of the conductive adhesive 30, and the conductive reinforcing member 35 and the conductive layer 22 have the same potential. can do. Therefore, the reinforcing member 35 having conductivity can have a shielding effect.

  Thereby, the reinforcing member 35 of the shield printed wiring board 1 has a dual function of reinforcing the mounting part of the electronic component 50 and shielding the noise such as the electromagnetic wave 90b from the outside with respect to the mounting part of the electronic component 50. It is possible to have at least.

  Each configuration will be specifically described below.

(Printed wiring board 10)
The printed wiring board 10 includes a base member 12 on which a plurality of wiring patterns such as a signal wiring pattern and a ground wiring pattern 14 (not shown) are formed, an adhesive layer 13 provided on the base member 12, and an adhesive layer. 13 and an insulating film 11 bonded to 13.

  Signal wiring patterns and ground wiring patterns 14 (not shown) are formed on the upper surface of the base member 12. These wiring patterns are formed by etching a conductive material. Of these, the ground wiring pattern 14 refers to a pattern that maintains the ground potential.

  The adhesive layer 13 is an adhesive interposed between the signal wiring pattern or the ground wiring pattern 14 and the insulating film 11, and has a role of maintaining the insulating property and bonding the insulating film 11 to the base member 12. . In addition, although the thickness of the adhesive bond layer 13 is 10 micrometers-40 micrometers, it does not need to be specifically limited and can be set suitably.

  Both the base member 12 and the insulating film 11 are made of engineering plastic. Examples thereof include resins such as polyethylene terephthalate, polypropylene, cross-linked polyethylene, polyester, polybenzimidazole, polyimide, polyimide amide, polyether imide, and polyphenylene sulfide. An inexpensive polyester film is preferable when heat resistance is not required, and a polyphenylene sulfide film is preferable when flame resistance is required, and a polyimide film is preferable when heat resistance is required. In addition, although the thickness of the base member 12 is 10 micrometers-40 micrometers, and the thickness of the insulating film 11 is 10 micrometers-30 micrometers, it does not need to be specifically limited and can be set suitably.

  The insulating film 11 and the adhesive layer 13 have a hole 40 formed by laser processing or the like. The hole 40 exposes a partial region of a wiring pattern selected from a plurality of signal wiring patterns and ground wiring patterns. In the case of this embodiment, the hole 40 is formed in the lamination direction in the insulating film 11 and the adhesive layer 13 so that a partial region of the ground wiring pattern 14 is exposed to the outside. The hole 40 has a hole diameter set appropriately so as not to expose other adjacent wiring patterns.

(Reinforcing member 35)
The reinforcing member 35 is made of a conductive material, for example, a stainless material. Further, the reinforcing member 35 is disposed on the shield film 20 so as to be opposed to the mounting part of the electronic component 50. By reinforcing the mounting part of the electronic component 50, distortion generated in the mounting part due to bending or the like. Is preventing. In addition, the reinforcing member 35 is not limited to a stainless steel material, and any material can be used as long as it can reinforce the mounting site and has conductivity, but because it has hardness suitable for reinforcement and excellent corrosion resistance, The use of stainless steel can more effectively reinforce the mounting part of the electronic component 50 and provide a shielding effect to the mounting part. Furthermore, in order to improve the electrical connection of the reinforcing member 35, it is preferable that the surface of the stainless steel is plated with nickel. The thickness of the reinforcing member 35 is 0.05 mm to 1 mm, and is appropriately determined depending on the configuration.

(Conductive adhesive 30)
The conductive adhesive 30 is formed of either an isotropic conductive or anisotropic conductive adhesive. An isotropic conductive adhesive has the same electrical properties as conventional solder. Therefore, when the conductive adhesive 30 is formed of an isotropic conductive adhesive, an electrically conductive state can be ensured in all three directions including the thickness direction, the width direction, and the longitudinal direction. . On the other hand, when the conductive adhesive 30 is formed of an anisotropic conductive adhesive, an electrically conductive state can be ensured only in a two-dimensional direction consisting of the thickness direction.

  The conductive adhesive 30 may be formed of a conductive adhesive in which conductive particles 32 mainly composed of a soft magnetic material and an adhesive 31 are mixed. In this case, since the conductive particles 32 exhibit high magnetization, a decrease in magnetic permeability is suppressed even for electromagnetic waves having a high frequency, so that radio waves can be absorbed. Thereby, in combination with the reinforcing member 35, in addition to the function of the shielding effect, it has a function of absorbing radio waves.

  Specifically, the conductive adhesive 30 is formed as a mixture of conductive particles 32 and an adhesive 31. That is, the conductive adhesive 30 is obtained by dispersing conductive particles 32 in the adhesive 31. The electrical connection of the conductive adhesive 30 is realized by continuously contacting one or more conductive particles 32 in the adhesive 31 in the thickness direction of the conductive adhesive 30. It is held by the adhesive force.

The adhesive 31 contained in the conductive adhesive 30 includes an acrylic resin, an epoxy resin, a silicon resin, a thermoplastic elastomer resin, a rubber resin, a polyester resin,
Urethane resin etc. are mentioned. The adhesive 31 may be a single substance or a mixture of the above resins. The adhesive 31 may further contain a tackifier. Examples of the tackifier include tackifiers such as fatty acid hydrocarbon resins, C5 / C9 mixed resins, rosin, rosin derivatives, terpene resins, aromatic hydrocarbon resins, and thermally reactive resins.

  Part or all of the conductive particles 32 included in the conductive adhesive 30 are formed of a metal material. For example, the conductive particles 32 may be copper powder, silver powder, nickel powder, silver-coated copper powder (Ag-coated Cu powder), gold-coated copper powder, silver-coated nickel powder (Ag-coated Ni powder), or gold-coated nickel powder. Yes, these metal powders can be produced by an atomizing method, a carbonyl method, or the like. In addition to the above, particles obtained by coating a metal powder with a resin and particles obtained by coating a resin with a metal powder can also be used. The conductive particles 32 are preferably Ag-coated Cu powder or Ag-coated Ni powder. This is because the conductive particles 32 having stable conductivity can be obtained from an inexpensive material. Note that the shape of the conductive particles 32 is not necessarily limited to a spherical shape. For example, a protrusion may be formed on a spherical surface based on the spherical shape. In this case, the conductive particles 32 can more easily break through the insulating layer 21. When the shape of the conductive particles 32 is spherical, the length of the conductive particles 30 protruding from the conductive adhesive 30 is almost the same in the layer thickness direction regardless of the direction in which the conductive particles are inclined in the conductive adhesive 30. It becomes constant. Thereby, for example, the conductive particles 32 are more likely to break through the insulating layer 21 and more easily come into contact with the conductive layer 22 than in a flake shape or a dendritic shape.

  In the conductive adhesive 30 having the above-described configuration, the thickness of the adhesive 31 is 5 μm to 40 μm, and the average particle diameter of the conductive particles 32 is 10 μm to 100 μm. Moreover, the average particle diameter of the conductive particles 32 with respect to the thickness of the adhesive 31 is 1.5 to 3 times. Therefore, part of the conductive particles 32 protrudes from the adhesive 31 of the conductive adhesive 30. The deviation of the average particle size of the conductive particles 32 is preferably ± 5 μm or less. In this case, since the protruding length of the conductive particles 32 protruding from the conductive adhesive 30 is not largely biased, the connection resistance with the conductive layer 22 is stabilized. Thereby, the reinforcing member 35 and the conductive layer 22 can be stably maintained at the same potential. Furthermore, the compounding quantity of the electroconductive particle 32 with respect to the adhesive agent 31 is 30 to 70 weight%, and 50 weight% is preferable from a viewpoint of adhesive force and electroconductivity.

(Shield film 20)
The shield film 20 includes a conductive layer 22 bonded to the conductive material 23 in a contact state, and an insulating layer 21 provided on the conductive layer 22.

  The conductive material 23 is formed of an adhesive having either isotropic conductivity or anisotropic conductivity. An isotropic conductive adhesive has the same electrical properties as conventional solder. Therefore, when the conductive material 23 is formed of an isotropic conductive adhesive, an electrically conductive state can be ensured in all three dimensions including the thickness direction, the width direction, and the longitudinal direction. On the other hand, when the conductive material 23 is formed of an anisotropic conductive adhesive, an electrically conductive state can be ensured only in a two-dimensional direction consisting of the thickness direction. Note that in the case where the conductive material 23 is formed of an isotropic conductive adhesive, the conductive material 23 may have the function of the conductive layer 22, and thus the conductive layer 22 may not be provided.

  The conductive material 23 includes an insulating adhesive and conductive particles dispersed in the insulating adhesive. Specifically, the insulating adhesive includes, as an adhesive resin, a polystyrene resin, a vinyl acetate resin, a polyester resin, a polyethylene resin, a polypropylene resin, a polyamide resin, a rubber resin, an acrylic resin, a phenol resin, an epoxy resin, and the like. It is composed of thermosetting resins such as styrene, urethane, melamine, and alkyd. In addition, conductive adhesive such as metal and carbon is mixed with these adhesive resins to obtain a conductive adhesive. When heat resistance is not particularly required, a polyester-based thermoplastic resin that is not restricted by storage conditions is desirable. When heat resistance or better flexibility is required, a highly reliable epoxy resin is required. A thermosetting resin is desirable. In either case, it is desirable to have a small bleeding (resin flow) during hot pressing. In addition, although the thickness of the electrically conductive material 23 is 3 micrometers-30 micrometers, it does not need to be specifically limited and can be set suitably.

  The conductive particles contained in the conductive material 23 have an average particle size smaller than the hole diameter of the hole 40 so as to enter the hole 40 described above. The conductive particles are partially or entirely formed of a metal material. For example, conductive particles include copper powder, silver powder, nickel powder, silver coat copper powder (Ag coated Cu powder), gold coated copper powder, silver coated nickel powder (Ag coated Ni powder), and gold coated nickel powder. These metal powders can be produced by an atomizing method, a carbonyl method, or the like. In addition to the above, particles obtained by coating a metal powder with a resin and particles obtained by coating a resin with a metal powder can also be used. The conductive particles are preferably Ag-coated Cu powder or Ag-coated Ni powder. This is because conductive particles having stable conductivity can be obtained from an inexpensive material. The shape of the conductive particles of the conductive material 23 is not necessarily limited to a spherical shape, and may be, for example, a flake shape or a dendritic shape.

  The conductive layer 22 has a shielding effect for shielding noise such as unnecessary radiation from an electric signal sent from the main board and external electromagnetic waves. The conductive layer 22 is a metal layer formed of nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc, and an alloy containing any one or more of these materials. The metal material may be appropriately selected depending on the required shielding effect, but copper has a problem that it is easily oxidized when exposed to the atmosphere, and gold is expensive. High silver is preferred. The film thickness may be appropriately selected according to the required shielding effect and repeated bending / sliding resistance, but a thickness of 0.01 μm to 10 μm is preferable. If the thickness is less than 0.01 μm, a sufficient shielding effect cannot be obtained, and if it exceeds 10 μm, flexibility becomes a problem. Furthermore, as a method for forming the conductive layer 22, there are vacuum deposition, sputtering, CVD, MO (metal organic), plating, foil, etc., but considering the mass productivity, vacuum deposition is desirable, and an inexpensive and stable conductive layer. 22 can be obtained. As described above, when the conductive material 23 is formed of an isotropic conductive adhesive, the conductive layer 22 may not be provided.

  The insulating layer 21 is formed of an epoxy-based, polyester-based, acrylic-based, phenol-based, or urethane-based resin, or a mixture thereof, and maintains insulation and prevents the conductive layer 22 from being directly exposed to the outside. It plays a role to cover. In addition, the thickness of the insulating layer 21 is 1 μm to 10 μm, and when the insulating layer 21 is formed by being directly coated on the conductive layer 22, for example, it can be made thinner than a film, and the conductive particles 32 can easily break through the insulating layer 21. Become.

  Further, when the reinforcing member 35 is provided on the shield film 20 with the conductive adhesive 30, the conductive adhesive 30 is bonded onto the insulating layer 21 in the shield film 20. At the time of bonding, the insulating layer 21 is heated from the reinforcing member 35 side and softened. As described above, the insulating layer 21 is softened by heating, so that the conductive particles 32 of the conductive adhesive 30 easily break through the insulating layer 21. Therefore, the epoxy resin or the like forming the insulating layer 21 is formed of a resin that is softened at the heating temperature when the reinforcing member 35 is provided on the insulating layer 21.

  Here, as shown in the enlarged portion a of FIG. 1, in the adhesion between the conductive adhesive 30 and the insulating layer 21, a part of the conductive particles 32 included in the conductive adhesive 30 is from the lower surface of the adhesive 31. The protruding portion of the conductive particle 32 penetrates the insulating layer 21 and comes into contact with the conductive layer 22. Therefore, the layer thickness L1 of the insulating layer 21 is set to be thinner than the protruding length L2 of the conductive particles 32 protruding from the conductive adhesive 30. Specifically, when the thickness of the adhesive 31 of the conductive adhesive 30 is 5 μm to 15 μm and the average particle diameter of the conductive particles 32 is 10 μm to 20 μm, the protruding length L2 of the conductive particles 32 is 5 μm to 15 μm. Therefore, the thickness of the insulating layer 21 is in the range of 2 μm to 12 μm. In the case of FIG. 1, the conductive particles 32 are arranged one by one in the layer thickness direction of the conductive adhesive 30, but for example, a plurality of conductive particles 32 are formed in the layer thickness direction of the conductive adhesive 30. The active particles 32 may overlap in two rows or three rows. That is, in the case of this embodiment, the reinforcing member 35 and the conductive layer 22 are electrically connected via one conductive particle 32 in the layer thickness direction of the conductive adhesive 30, but this is not a limitation. In the layer thickness direction of the conductive adhesive 30, a plurality of conductive particles 32 are overlapped, and the reinforcing member 35 and the conductive layer 22 are electrically connected via the plurality of conductive particles 32. May be. The layer thickness of the insulating layer 21 may be set so as to be thinner than the protruding length of the conductive particles 32 protruding from the conductive adhesive 30.

  In the shield film 20 having the above configuration, the conductive material 23 flows into the hole 40 and contacts the ground wiring pattern 14 exposed to the outside. As a result, the conductive layer 22 is electrically connected to the ground wiring pattern 14 via the conductive material 23 bonded in a contact state, and is kept at the same potential. Thus, the shield film 20 has a shielding effect and can shield noise such as the electromagnetic wave 90a from the outside.

  Further, the shield film 20 is arranged in a state extending to a region facing the mounting part of the electronic component connected to the printed wiring board 10. Thereby, using the shield film 20, it is possible to shield noise such as the electromagnetic wave 90b from the outside with respect to the mounting part of the electronic component 50.

  In addition, the conductive particles 32 protruding from the lower surface of the conductive adhesive 30 can break through the insulating layer 21 of the shield film 20 and come into contact with the underlying conductive layer 22. As a result, the reinforcing member 35 and the conductive layer 22 of the shield film 20 become conductive through the conductive particles 32 of the conductive adhesive 30, and the conductive reinforcing member 35 and the conductive layer 22 have the same potential. can do.

  As described above, the shield printed wiring board 1 according to this embodiment includes the base member 12 on which the ground wiring pattern 14 is formed, and the insulating film 11 provided on the base member 12 so as to cover the ground wiring pattern 14. And the printed circuit board 10 connected to the mounting portion provided on the lower surface of the base member 12 and the region having the same potential as the ground wiring pattern 14 and facing the mounting portion. The conductive layer 22 and the insulating layer 21 provided on the conductive layer 22, and the shield film 20 provided on the printed wiring board 10 and disposed in a region facing the mounting portion. A shield printed wiring board 1 having a conductive reinforcing member 35 provided thereon, the reinforcing member 35 having a spherical conductive property The conductive layer 30 is bonded to the insulating layer 21 by the conductive adhesive 30 including the child 32, and the insulating layer 21 protrudes from the conductive adhesive 32 protruding from the conductive adhesive 30 after the conductive adhesive 30 is bonded. After the conductive adhesive 30 is bonded to the insulating layer 21, the conductive particles 32 come into contact with the conductive layer 22.

  According to the above configuration, the conductive layer 22 having the same potential as the ground wiring pattern 14 is disposed on the printed wiring board 10 up to a region facing the mounting portion of the electronic component 50. Thereby, the electromagnetic wave 90a from the outside with respect to the mounting part of the electronic component 50 can be shielded by the shield film 20 having the conductive layer 22. In addition, the region facing the mounting part of the electronic component 50 is reinforced by the reinforcing member 35 provided on the shield film 20. Thereby, the distortion etc. which arise in a mounting site | part resulting from a bending etc. by the reinforcement member 35 can be prevented. Furthermore, after the conductive particles 32 contained in the conductive adhesive 30 that bonds the reinforcing member 35 on the insulating layer 21 of the shield film 20 are bonded, the conductive layer 22 of the shield film 20 is bonded. Therefore, the electric potential of the reinforcing member 35 having conductivity and the electric potential of the conductive layer 22 can be set to the same electric potential, and the reinforcing member 35 can also have a shielding effect. Thereby, the shielding effect can be more reliably brought about by the double effect of the shielding effect by the shielding film 20 and the shielding effect by the reinforcing member 35 on the mounting part of the electronic component 50. Therefore, in order to set the reinforcing member 35 to the ground potential, it is not necessary to expose the ground wiring pattern 14 and connect the reinforcing member 35 and the ground wiring pattern 14 via the conductive adhesive as in the prior art. Therefore, it is not necessary to form the ground wiring pattern 14 in accordance with the location of the reinforcing member 35, and the degree of freedom in design is improved. Furthermore, since there is no need to connect the reinforcing member 35 and the ground wiring pattern 14 via a conductive adhesive, there is no problem during reflow caused by a gap formed in the connecting portion. As described above, the shielding effect can be maintained while ensuring the degree of freedom of design. Furthermore, since the conductive particles 32 are spherical, the length of the conductive particles 32 protruding from the conductive adhesive 30 is almost constant in the layer thickness direction regardless of the direction in which the conductive particles 32 are inclined. become. Thereby, for example, the conductive particles 32 are more likely to break through the insulating layer 21 and more easily come into contact with the conductive layer 22 than in the form of flakes or dendrites. As a result, the reinforcing member 35 and the conductive layer 22 can be more reliably maintained at the same potential.

  In the shield printed wiring board 1 according to the present embodiment, the printed wiring board 10 includes a base member 12 on which the ground wiring pattern 14 is formed and an insulation provided on the base member 12 so as to cover the ground wiring pattern 14. The insulating film 11 further includes a hole 40 that exposes a part of the ground wiring pattern 14. The conductive layer 22 of the shield film 20 is provided on the insulating film 11 and has a hole. The conductive material 23 filled in the portion 40 is provided in contact.

  According to the above configuration, the potential of the conductive layer 22 of the shield film 20 and the potential of the ground wiring pattern 14 are set to the same potential via the conductive material 23 filled in the hole 40 formed in the insulating film 11. can do. This eliminates the need to bother connecting to an external ground member in order to set the potential of the conductive layer 22 to the ground potential.

  In the shield printed wiring board 1 according to this embodiment, the insulating layer 21 of the shield film 20 is coated on the conductive layer 22.

  According to said structure, since the insulating layer 21 of the shield film 20 is coated on the conductive layer, for example, it can be made thinner than the film-like insulating layer 21, and the conductive property protruded from the conductive adhesive 30 can be reduced. The particles 32 break through the insulating layer 21 and easily come into contact with the conductive layer 22.

  Further, in the shield printed wiring board 1 according to the present embodiment, the reinforcing member 35 is formed of a stainless material.

  According to the above configuration, since the stainless steel has hardness suitable for reinforcement and excellent corrosion resistance, it can more effectively reinforce the mounting part of the electronic component 50 and provide a shielding effect to the mounting part. .

  In the present embodiment, the reinforcing member 35 may be further connected to an external ground member maintained at the same potential as the ground wiring pattern 14. That is, a grounding member having the same potential as that of the grounding wiring pattern 14 may be separately prepared outside, and the reinforcing member 35 and the grounding member may be further connected by using wiring or the like. According to this, the reinforcing member 35 is internally maintained at the same potential as the ground wiring pattern 14 via the conductive particles 32 contained in the conductive adhesive 30 and is also grounded via the external ground member. Since the same potential as the wiring pattern 14 is maintained, the shielding effect can be further improved.

(Method for manufacturing shield printed wiring board 1)
Next, the manufacturing method of the shield printed wiring board 1 which concerns on this embodiment is demonstrated using FIG. 2 and FIG. As shown in FIGS. 2 and 3, the method for manufacturing the shield printed wiring board 1 according to the present embodiment includes a hole forming process for forming the hole 40 in the insulating film 11 of the printed wiring board 10, A shield film bonding step for providing the shield film 20 on the upper surface of the shield film, a peeling layer peeling step for peeling the release layer 28 located on the uppermost surface of the shield film 20, and a conductive adhesive 30 on the upper surface of the insulating layer 21 of the shield film 20. The electronic component 50 is connected to the lower surface of the printed wiring board 10 at a position facing the reinforcing member 35, the conductive adhesive bonding step for bonding the reinforcing member 35 to the conductive adhesive 30, and the reinforcing member bonding step for bonding the reinforcing member 35 to the conductive adhesive 30. And an electronic component connecting step.

  Hereafter, each process is demonstrated concretely. As shown in FIG. 2A, in the hole forming step, first, a printed wiring board 10 is prepared. Then, the hole 40 is formed in the insulating film 11 and the adhesive layer 13 of the printed wiring board 10 by laser processing or the like. Through this process, a part of the ground wiring pattern 14 selected from the plurality of signal wiring patterns and ground wiring patterns is exposed to the outside through the hole 40.

  Next, as shown in FIG. 2B, in the shield film bonding step, the shield film 20 is bonded onto the insulating film 11 of the printed wiring board 10. At the time of bonding, the printed wiring board 10 and the shield film 20 are pressure-bonded from above and below by the press machine P while the conductive material 23 of the shield film 20 is heated by the heater h. As a result, the conductive material 23 of the shield film 20 is softened by the heat of the heater h, and is adhered onto the insulating film 11 by pressurization of the press machine P and filled in the hole 40. Then, the conductive material 23 filled in the hole 40 comes into contact with the ground wiring pattern 14 before long. Through this step, the shield film 20 is provided on the insulating film 11 of the printed wiring board 10, and the conductive layer 22 of the shield film 20 and the ground wiring pattern 14 are electrically connected via the conductive material 23. As a result, the conductive layer 22 of the shield film 20 and the ground wiring pattern 14 are kept at the same potential, and the shield film 20 can shield noise such as an electromagnetic wave 90a from the outside.

  Next, as shown in FIG.2 (c), in the peeling layer peeling process, the peeling layer 28 previously provided in the uppermost surface of the shield film 20 is peeled.

  Next, as shown in FIG. 3D, in the conductive adhesive bonding step, the conductive adhesive 30 is bonded onto the insulating layer 21 of the shield film 20. In this step, the conductive adhesive 30 is temporarily bonded onto the insulating layer 21.

  Next, as shown in FIG. 3E, the reinforcing member 35 is bonded onto the conductive adhesive 30 in the reinforcing member bonding step. At the time of bonding, the shield film 20 provided on the printed wiring board 10 and the reinforcing member 35 are pressure-bonded from above and below by the press machine P through the cushioning material 60 while heating the conductive adhesive 30 by the heater h. To do. Thereby, the adhesive 31 of the conductive adhesive 30 is softened by the heat of the heater h, and the conductive particles 32 protrude from the adhesive 31 by the press of the press P. Then, the conductive particles 32 protruding from the conductive adhesive 30 break through the insulating layer 21 softened by the heat of the heater h by the press of the press machine P, and eventually come into contact with the conductive layer 22. The heating temperature of the heater h is 150 ° C. to 190 ° C., and the pressure of the press machine P is 2 MPa to 5 MPa. Moreover, the pressurization time by the press machine P is 5 minutes-60 minutes. Through this step, the reinforcing member 35 is provided on the shield film 20, and the reinforcing member 35 and the conductive layer 22 of the shield film 20 are electrically connected via the conductive particles 32. Accordingly, the reinforcing member 35, the conductive layer 22, and the ground wiring pattern 14 are kept at the same potential, and the reinforcing member 35 can also have a shielding effect.

  Finally, as shown in FIG. 3F, in the electronic component connecting step, the electronic component 50 is connected to the mounting portion on the lower surface (the lower surface in the drawing) of the printed wiring board 10. At this time, the conductive layer 22 of the shield film 20 is disposed on the upper surface (the upper surface in the drawing) of the printed wiring board 10 up to a region facing the mounting portion of the electronic component 50. Thereby, the electromagnetic wave 90b from the outside with respect to the mounting part of the electronic component 50 can be shielded by using the shield film 20. Further, a reinforcing member 35 is disposed on the upper surface (upper surface in the drawing) of the shield film 20 so as to face the mounting portion of the electronic component 50. Thereby, the electromagnetic wave 90b from the outside with respect to the mounting site | part of the electronic component 50 can be more reliably shielded by the shielding effect of the reinforcing member 35.

  In the conductive adhesive bonding step shown in FIG. 3 (d) and the reinforcing member bonding step shown in FIG. 3 (e), the conductive adhesive 30 is first applied onto the insulating layer 21, and then the reinforcing member 35. Is bonded to the conductive adhesive 30, but the member in which the reinforcing member 35 and the conductive adhesive 30 are bonded together may be pasted on the insulating layer 21. However, since the adhesiveness is better when the conductive adhesive 30 is bonded to the insulating layer 21 than when the conductive adhesive 30 is bonded to the reinforcing member 35, the manufacturing method according to the present embodiment is more workable. Good and easy to manufacture.

(Examples and comparative examples)
Next, the present invention will be specifically described with reference to examples of the shield printed wiring board 1 according to the present embodiment and comparative examples. Details and experimental results of the examples and comparative examples are shown in FIG.

  As shown in FIG. 4, Examples 1 to 5 and Comparative Examples 1 and 2 have the same configuration as that of the shield printed wiring board 1 according to the present embodiment shown in FIG. Uses the same configuration as that of the conventional shield printed wiring board 100 shown in FIG. More specifically, in the connection form between the reinforcing member and the ground wiring pattern, Examples 1 to 5 and Comparative Examples 1 and 2 have the same connection form as the shield printed wiring board 1 according to the present embodiment. Only Comparative Example 3 has the same connection form as the conventional shield printed wiring board 100. Here, in the printed wiring boards 10 and 110 used in the examples and comparative examples, the thickness of the base members 12 and 112 is 25 μm, the thickness of the ground wiring patterns 14, 114 and 115 is 18 μm, the adhesive layer 13, The thickness of 113 is 25 μm, and the thickness of the insulating films 11 and 111 is 12 μm. In the shield films 20 and 120 used in the examples and comparative examples, the conductive materials 23 and 123 have a thickness of 10 μm, the conductive layers 22 and 122 have a thickness of 0.1 μm, and the insulating layers 21 and 121 have a thickness of 5 μm. is there. The reinforcing members 35 and 135 are made of conductive nickel-plated stainless steel and have a thickness of 0.2 mm.

  Furthermore, in Examples 1 to 5 and Comparative Examples 1 and 2, the thickness of the conductive adhesive 30 for bonding the reinforcing member 35 to the insulating layer 21 is 10 μm, and the average particle diameter of the conductive particles 32 is shown in FIG. Each is set as shown. In addition, the deviation of the average particle diameter of the conductive particles 32 of the example is ± 5 μm or less. For example, in the case of Example 1, the average particle diameter of the conductive particles 32 is 5 μm, and the thickness of the conductive adhesive 30 and the conductive particles 32 after the reinforcing member 35 is bonded to the insulating layer 21 is 10 μm. . In the case of this Example 1, since the average particle diameter (5 μm) of the conductive particles 32 is smaller than the thickness (10 μm) of the conductive adhesive 30, the conductive particles 32 are buried in the conductive adhesive 30. The thickness after bonding (10 μm) is the same as the thickness of the conductive adhesive 30. In the case of Example 1, since the particle diameter of the conductive particles 32 is 10 μm at the maximum even when the deviation is taken into consideration, the conductive particles 32 exist in a form buried in the conductive adhesive 30. For example, in the case of Example 2, the average particle diameter of the conductive particles 32 is 10 μm, and the thickness of the conductive adhesive 30 and the conductive particles 32 after the reinforcing member 35 is bonded to the insulating layer 21 is 10 μm. It becomes. In the case of Example 2, the average particle diameter (15 μm in consideration of deviation) of the conductive particles 32 is larger than the thickness (10 μm) of the conductive adhesive 30, and the conductive particles 32 protruding from the conductive adhesive 30. The protrusion length (5 μm) of the insulating layer 21 is the same as the thickness (5 μm) of the insulating layer 21. Therefore, when the deviation of the average particle diameter of the conductive particles 32 is taken into consideration, the conductive particles 32 protruding from the conductive adhesive 30 have just broken through the insulating layer 21 and are in contact with the conductive layer 22 therebelow.

  Moreover, as shown in FIG. 4, the shape of the electroconductive particle 32 of the electroconductive adhesive 30 in Examples 1-5 is spherical. And the shape of the electroconductive particle 32 of the electroconductive adhesive 30 in the comparative example 1 is flake shape, and the shape of the electroconductive particle 32 of the electroconductive adhesive 30 in the comparative example 2 is dendritic. Furthermore, the shape of the conductive particles of the conductive adhesive 130 in Comparative Example 3 is set to a dendritic shape. In all Examples and Comparative Examples, the blending amount of the conductive particles is unified to 50% by weight.

  Using the Examples and Comparative Examples set as described above, the connection resistance between the reinforcing member and the ground wiring pattern was measured. Further, a comprehensive evaluation was made by combining the measured connection resistance value and the result of judging the reflow resistance in the reflow process performed using heat of about 260 ° C. Here, the measured value of the connection resistance between the reinforcing member and the ground wiring pattern is “◯” when less than 0.5Ω, “△” when 0.5Ω or more and less than 10.0Ω, and “×” when 10.0Ω or more. Judgment criteria were established. As for reflow resistance, pass / fail “○”, “△”, and “×” were determined by electrical inspection such as appearance inspection and shield inspection after mounting.

  As a result, with respect to the reflow resistance, Comparative Example 3 expanded due to the inclusion of voids and became “x” which failed in the appearance inspection and the like. As a reason for this, since Comparative Example 3 has the same connection form as the conventional shield printed wiring board 100 shown in FIG. 5 in the connection form between the reinforcing member and the ground wiring pattern, the conductive adhesive It is considered that an air gap has entered the connecting portion between 130 and the ground wiring pattern 115. That is, in the case of the conventional shield printed wiring board 100, the connecting portion between the reinforcing member 135 and the ground wiring pattern 115 is sandwiched between the upper and lower hard materials. Therefore, the conductive adhesive 130 does not follow. As a result, the gaps 160a and 160b enter the connection part between the conductive adhesive 130 and the ground wiring pattern 115, and the gaps expand due to heat generated by the reflow process, so that the appearance defect and the shielding effect cannot be maintained. It is probable that this problem occurred. Moreover, about Example 5, it became "(triangle | delta)" by the external appearance test | inspection etc. because some space | gap mixed. This is because, in Example 5, the average particle diameter of the conductive particles 32 is 30 μm, and the average particle diameter of the conductive particles 32 is too large with respect to the thickness of the conductive adhesive 30 and the insulating layer 21. It is considered that a large gap is formed between the conductive adhesive 30 and the insulating layer 21, and some gaps may be mixed in the gap.

  On the other hand, Examples 1 to 4 and Comparative Examples 1 and 2 have the same connection form as that of the shield printed wiring board 1 of the present embodiment in the connection form between the reinforcing member and the ground wiring pattern. Since the average particle diameter of the particles 32 was not too large, there was no problem as in Comparative Example 3 and Example 5, and the reflow resistance satisfied the acceptance criteria of “◯”.

  In addition, the connection resistance between the reinforcing member and the ground wiring pattern is that Examples 2 to 5 and Comparative Example 3 satisfy the criteria of “◯”, Example 1 is “△”, and Comparative Examples 1 and 2 are It was “×”. This is because, in Comparative Examples 1 and 2, the conductive particles are in the form of flakes or dendrites, and depending on the inclination state of the conductive particles, the insulating layer 21 cannot be pierced and the reinforcing member 35 is kept at the ground potential. It is thought that it was not possible. In Example 1, since the average particle diameter of the conductive particles 32 is the same as or smaller than the thickness of the conductive adhesive 30 even when the deviation is taken into account, the protrusion of the conductive particles 32 from the conductive adhesive 30 is small. It is thought that it was difficult to contact the conductive layer 22.

  On the other hand, in Examples 2 to 5, since the average particle diameter of the conductive particles 32 is appropriate with respect to the thickness of the conductive adhesive 30 and the thickness of the insulating layer 21, conduction between the reinforcing member 35 and the conductive layer 22 is achieved. The state is stable. As a result, the connection resistance between the reinforcing member 35 and the ground wiring pattern 114 could be maintained at 0.5Ω or less. In the case of Comparative Example 3, the connection resistance between the reinforcing member 135 and the ground wiring pattern 115 is such that the gaps 160a and 160b enter the connection between the conductive adhesive 130 and the ground wiring pattern 115. The conductive state of the reinforcing member 135 and the ground wiring pattern 115 was maintained by the conductive adhesive 130 in a shape, and could be reduced to 0.5Ω or less.

  From the above experimental results, when the judgment based on the connection resistance between the reinforcing member and the ground wiring pattern and the judgment based on the reflow resistance are comprehensively evaluated with “◯”, “Δ”, “×”, Examples 2 to 4 Was “◯”, Examples 1 and 5 were “Δ”, and Comparative Examples 1 to 3 were “x”. From this result, it can be seen that if the connection form of the reinforcing member 35 and the ground wiring pattern 14 in the shield printed wiring board 1 of the present embodiment is used, the acceptance criterion of “Δ” or more is satisfied in the reflow resistance. The connection resistance between the reinforcing member and the ground wiring pattern is “Δ” when the conductive particles 32 protruding from the conductive adhesive 30 are in contact with the conductive layer 22 in the shield printed wiring board 1 of the present embodiment. It can be seen that the above pass criteria are met. Furthermore, the average particle diameter of the conductive particles 32 is appropriate as compared with the thicknesses of the conductive adhesive 30 and the insulating layer 21, and as a result, the gap formed between the conductive adhesive 30 and the insulating layer 21 has a deviation. If it is considered to be up to 10 μm (in the case of Example 4), it can be seen that both the connection resistance and the reflow resistance are good, and the pass criterion of “◯” is satisfied in the comprehensive evaluation.

  The embodiments of the present invention have been described above. Note that the present invention need not be limited to the above-described embodiment.

  For example, in the shield printed wiring board 1 according to the present embodiment, the reinforcing member 35 breaks through the insulating layer 21 by the protruding portions of the conductive particles 32 protruding from the conductive adhesive 30 and has the same potential as the ground wiring pattern 14. Although it is in contact with the conductive layer 22, the reinforcing member 35 and the conductive layer 22 may be kept at the same potential using other means. For example, by using a laser or the like, a plurality of holes that expose the conductive layer 22 to the outside are formed on the surface of the insulating layer 21, and a conductive adhesive containing dendritic conductive particles is applied thereon. Thus, the conductive particles may be poured into the hole portion so that the conductive particles and the conductive layer 22 are in contact with each other. According to this, the reinforcing member 35 and the conductive layer 22 can be kept at the same potential via the conductive adhesive containing the dendritic conductive particles filled in the hole.

  The embodiments of the present invention have been described above, but only specific examples have been illustrated, and the present invention is not particularly limited. Specific configurations and the like can be appropriately changed in design. Further, the actions and effects described in the embodiments of the present invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to things.

  The present invention can be applied to a shield printed wiring board used for electronic devices such as a mobile phone and a computer.

DESCRIPTION OF SYMBOLS 1 Shield printed wiring board 10 Printed wiring board 11 Insulating film 12 Base member 13 Adhesive layer 14 Grounding wiring pattern 20 Shield film 21 Insulating layer 22 Conductive layer 23 Conductive material 30 Conductive adhesive 31 Adhesive 32 Conductive particle 35 Reinforcement Member 40 hole 50 electronic component 90a electromagnetic wave 90b electromagnetic wave

Claims (4)

A mounting portion having a base member on which a ground wiring pattern is formed and an insulating film provided on the base member so as to cover the ground wiring pattern and an electronic component provided on the lower surface of the base member A printed wiring board connected to
A conductive layer that has the same potential as the ground wiring pattern and is disposed up to a region facing the mounting site; and an insulating layer provided on the conductive layer, and is provided on the printed wiring board. A shield film,
A reinforcing member having conductivity, disposed in a region facing the mounting part, and provided on the shield film;
A shielded printed wiring board having
The reinforcing member is adhered onto the insulating layer by a conductive adhesive containing spherical conductive particles,
The insulating layer is formed with a layer thickness thinner than the protruding length of the conductive particles protruding from the conductive adhesive after the conductive adhesive is bonded,
The shield printed wiring board, wherein the conductive particles come into contact with the conductive layer after the conductive adhesive is bonded to the insulating layer.   The shield printed wiring board according to claim 1, wherein the reinforcing member is further connected to an external ground member maintained at the same potential as the ground wiring pattern.   The shield printed wiring board according to claim 1, wherein the insulating layer of the shield film is coated on the conductive layer.   The shield printed wiring board according to claim 1, wherein the reinforcing member is made of a stainless material.